There must have been a moment at the beginning, where we could have said no. Somehow we missed it. Well, we'll know better next time.
My wife and I have played the West End Adventures cases, and we wanted to know if there was a version of this item with only the Ripper cases, or if a future item will be released combining the Ripper cases with other cases we have not already solved.
Another option you could consider, if what you request doesn't ever become available retail - these are one-and-done games, i.e. most people will not likely re-play cases. So as people start finishing this new expansion, they should start appearing on the secondary market for cheaper. So it wouldn't sting as much to buy the whole thing.
Or, you might find someone willing to separate it out and sell you just the used Ripper cases second-hand.